Undertale One Shots
by Undertaleismylife
Summary: WARNING: LEMONS AND SHIT Main focused Characters: Sans, Papyrus, Mettaton, and requested characters
1. Sans x Reader

You've been staying at Sans and Papyrus's house for about four months by now. You could say you have grown fond of the two skelebros. You liked Papyrus's optimistic attitude and how he's unintentionally hilarious at times, but you've particularly grown fond to Sans. Who wouldn't? He's an adorable skeleton who likes to make people laugh.

You've been sleeping in Sans room since Papyrus's room was too small, so the skelebros bought you a bed and put it in Sans' room. You were currently laying down on your bed as Sans slept across from you. He was so cute when he was asleep, though you'd never admit it. You've always had a crush on Sans since you met him and always wondered what it'd be like to kiss him. You decided that now was your opportunity.

You got up and walked towards the sleeping skeleton. You looked around for a second to make sure the door was locked as you got up and sat on top of where his stomach should've been if he were a human. You grabbed either sides of his face and pressed your lips against his mouth. When you pulled away, you seen Sans looking at you, blushing a cyan blue as he put his arm around your waist.

"Heh, feeling sorta _bonely?_ " Sans asked, smirking as your face turned completely red.

"I-I..." you began.

"Nah, I guess you could say that I like you too..." Sans said.

"Wh-what?" You said, blushing even more.

"Yea, I love every bone in your body," Sans said, blushing even more.

"S-Sans, you can't be serious," you said.

"I'm _dead_ serious" Sans said with a wink as you chuckled.

"Sans, do you really?" you asked.

"Yep."

"Well then I like you too, _tibia_ honest. Ha! Take that, Sans!" you exclaimed.

Sans became flustered as his left eye began to turn cyan like his face. He came closer to you and brushed your hair out of your face before pressing his lips on yours. (do skeletons even have lips? im confused .-.) He summoned a tongue with his magic and asked for entrance. You allowed him as he explored your mouth, fighting for dominance. You let him win as you parted your lips for air, both of you completely flustered, especially Sans who was sweating by now.

Sans picked you up and held you on top of his hips as he pulled you in for another kiss. After you pulled away, you felt a slight bulge in his pants and started blushing even more. You smirked as you moved your hips back and forth. Sans realized what was happening and started to get flustered again as he tried to hide his face in his jacket.

"Heh, someone has a _bone_ -er!~" you sang as you pecked Sans on the cheek.

"Hehe, nice one," Sans whispered.

You decided to make Sans even more embarrassed because you thought it was adorable when he was flustered. You took off your shirt and pants along with your bra as he blushed even more, trying to avoid looking at your breasts to be polite. You grabbed his hand and put it on your breast, leading it down to your inner thigh. You took off his basketball shorts and observed his length as you took a long lick as Sans let out a barely audible moan. You repeated again as he moaned a bit louder, but then stopped and went back up to kiss him, caressing his ribs as he moaned a bit louder.

"okay kid, how about I do something instead of just sitting here?" Sans said as he flipped you over and took off your panties. "Heh, how about I... _BONE_ you?"

He teased your lips as you moaned softly.

"Do ya wanna have a good time?" Sans said as he kissed you to calm you down as he slid in.

You moaned into the kiss as you tried to accommodate his length. After a few minutes you were used to it.

"Y-you can move now," you said, trying not to moan.

You moaned as Sans started rocking his hips into you slowly, kissing you as you fondled his ribcage. He sped up the pace as you moaned even louder. You started moaning even more when he hit your spot. You rolled your hips as drool came out of your mouth. But suddenly, he stopped for a bit.

"W-wow, that's all it took?" Sans said, chuckling softly while catching his breath.

"I must be pretty g-good at this, eh?" he said as he picked you up as you straddled him and started bouncing your hips up and down.

You moaned as you kissed him yet again, rolling your hips against your spot. You kept on doing this until you seen white clouding your vision as your moans caught your throat. Sans' thrusts sped up as he moaned softly, filling you up. You were sitting still like that for a moment as you caught your breath and then slid off of him, pecking him on his cheek.

"So I guess I could say you threw me a _bone_?" you said as he chuckled.


	2. Papyrus x Reader (hides in trashbin)

**A/N: Requested by a friend, but why would you do this to Papyrus!? I won't question you though e,e**

Your heart beat at a million miles an hour as you cooked spaghetti with the skeleton you loved more than anything. Papyrus. He was a cute innocent cinnamon bun who always knew how to brighten up your day. Along with that, his innocent little smile had also managed to steal your heart.

"HUMAN! WOULD YOU LIKE TO STIR THE SAUCE WHILE I GO GRAB THE EXTRA INGREDIENTS?" Papyrus said innocently. He always added 'extra ingredients' that made his pasta 'greater'. These extra ingredients included glitter and sprinkles.

"Sure," you answered nervously as he grabbed the extra ingredients from the cabinet.

After the spaghetti was finished, you made Papyrus and you a plate and sat down at the table. Sans was at his so called job at a hotdog stand, leaving you both home alone. You've been hiding your feelings for Papyrus for so long. You've decided to speak up. Your voice disagreed with you as you managed to face your fears.

"P-Papyrus…" you started.

"YES, HUMAN..?" Papyrus said, urging you to go on.

"I-I…" you lost your words for a second before quickly saying what you were thinking and have been thinking for the past few months. "Ithinkiloveyou.."

It took Papyrus a minute to process your words as his face was in one of confusion. The second he found out what you said, his face flushed a bright orange.

"H-HUMAN… I THINK I LIKE YOU TOO, I MEAN YOU ARE GREAT," Papyrus said, his face growing even more orange with every word.

"Y-You do?" you stuttered out as Papyrus gave a slow nod.

You suddenly felt sort of confident as you pulled Papyrus to his room, pushing him onto his bed, and, without thinking, grabbed the skeleton's face. You pressed your mouth against his teeth, mimicking a kiss as he became flustered. Papyrus suddenly realized that you were kissing him, (as naive as he is) and kissed back, asking for an entrance. You parted your mouth ever so slightly as he explored your mouth. You wondered how he knew how to kiss, but the thought quickly left your mind as he kissed with more passion than before, eliciting a moan from you before he pulled away.

"H-Human… what was that sound you made? Did I hurt you..?" Papyrus said, his voice low as you chuckled at how naive he was.

"N-No, it just f-felt good is all…" you explained nervously.

"O-oh.." Papyrus said, smirking as lust filled his normally child-like eyes. "What about this, I've heard this does too on h-humans.."

Papyrus began to kiss your neck as you let out another small moan. He began to trail kisses on your collarbone too as you moaned a bit louder, but still soft. You decided you needed to take control as you flipped Papyrus on his back and started to caress his ribs.

"H-Human.. What are you doing?" Papyrus said, becoming flustered as he felt himself get a _bone_ -er. (wow im sorry but im not sorry) "Uh...h-human.."

You were going to stop there but curiosity got the best of you as you pulled down Papyrus's shorts to see an orange member. You hesitated for a moment before giving a long lick, causing Papyrus to moan before he stood up.

" **So you wish to please a royal guardsman?** " Papyrus's voice sounded husky, lust taking over him in an attitude that was completely unexpected of him as you sat on your knees before him. " **Suck.** "

You gave another lick before taking some of it into your mouth. He moaned as you suckled on the head before taking in more. You felt it hit the back of your throat as you did so. You tried to swallow some saliva as you tried to control your gag reflex, resulting in your throat massaging it.

" **H-human…"** Papyrus said as he slid out of your mouth, flipping you over.

" **Brace yourself."**

After having said that, he slowly slid some of it in, stretching you out. You let out a moan as he paused for a moment for you to adjust to it. You gave him an approving nod after a few moments and he started to move, gradually picking up the pace. You moaned his name as he began to set up a steady, fast pace. You finally reached your peak after a few more thrusts, triggering his too as he came. He pulled out as you both laid there, panting.

"I love you, Papy," you said, hugging him as you laid your head on his chest.

"You too, (Y/N),) Papyrus said, kissing your forehead.

 **A/N: *hides in trashcan* DON'T KILL ME FOR WHAT I DID TO THE CINNAMON ROLL!**


	3. Chapter 3: Undyne and Alphys x m Reader

**A/N: This is my second requested story so far! (woot woot! c;) But I do admit I am nervous about this because I've only written one male x reader in my life but eh.. I'll get over this! Hope you enjoy! :3**

You woke up from a long night's sleep. You had started dating Alphys and Undyne a few months ago. People would ridicule you for not only dating two girls at once, but also monsters. But honestly, you didn't care, just as long as you had your two girlfriends you were happier than the richest man alive. Alphys stirred in her sleep peacefully before she opened her eyes and sat up.

Alphys stood up from the bed, you following. You two walked into the kitchen where Undyne was cooking some pancakes. Oh dear...

"U-Undyne, be a little m-more c-careful with t-the-" Alphys stuttered before a pancake hit the ceiling.

"Awww dammit!" Undyne said, looking at the half-cooked pancake that decorated the ceiling, gasping when it hit her in the head.

Alphys and you failed at holding in your laughter as she peeled it off of her face with her hand. At least she had successfully cooked five burnt pancakes..? The three of you sat down at the table and ate the pancakes.

"I-I've heard they're making a M-Mew Mew Kissy C-Cutie 3," Alphys said. "T-They already r-ruined M-Mew Mew's character a-arc so w-why do they need a-another one?"

"To fix it..?" Undyne guessed. "Hell if I know.."

After eating breakfast, you all went into the bedroom to watch the news like you did every day. Nothing important happened, as always. You were going to change the channel, but accidentally flipped to the porn channel. Your face turned dark red as Undyne bursted out laughing at your reaction.

"I didn't even rent this channel!" You protested.

"Haha! I did a long time ago!" Undyne said, still laughing at your face.

Your face got redder as you felt yourself get hard. You immediately grabbed a pillow to cover it, but it was too late.

"Pfffttt haha!" Undyne laughed.

"S-Stop Undyne!" Alphys said, her face red as well.

Undyne whispered something into Alphys' ear as she nodded. When you were distracted, Undyne slipped her hand down your pants, causing you to gasp before melting into the touch. She pumped up and down on your member, her face turning red too.

After a few more pumps, she pulled away. Alphys turned off the TV while Undyne began to grind in your lap. You tried to suppress a moan but failed as you felt a wet spot forming in her panties. Alphys walked over to you and started kissing you shyly. You asked for entrance, exploring her mouth with lust.

After a few minutes, panties and clothes were off. You tried not to stare at them for too long as you bounded over to Alphys, who was trying to cover herself up. You kissed her yet again, more passionately this time, as you gently moved her arms from her chest, squeezing her breasts as she moaned softly into the kiss.

You two broke the kiss as you sat on the bed. Undyne crawled between your legs and put her mouth around the tip of your member. She took it in, suckling on it as you suppressed another moan from slipping out. Soon she had most of it in, reaching the back of her throat.

You felt yourself getting close. Undyne sensed this and pulled away, much to your disappointment. Soon, her mouth was replaced with something much better. Alphys had sat herself down on your cock, her face absolutely flustered.

She moaned as she waited to get used to the feeling. After waiting for a minute or two, she moved her hips up and down as Undyne passionately kissed you on the lips. You thrusted every few times she'd sit back down on your member, eliciting a louder moan from her when you did.

After a few minutes, you were reaching your peak. Alphys got off of your cock and finished you with her mouth, deepthroating you as much as she could. You came down her throat as she swallowed the fluid. At least there'd be no cleanups.

"T-That's our thanks f-for being o-our amazing b-boyfriend!" Alphys said in between pants.

This was a great morning. Definitely not like your daily routine, not at all.

 **A/N: AAAAAAA HIDE ME (and yes undyne was masturbating in the background lol)**

 **Sorry if this wasn't that good by the way, i was trying not to make it feel rushed but you know I'm not that great at wording things and such...**


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